结合二叉树遍历算法，在下列二叉树遍历的应用中任选一题完成。 1. 统计二叉树中叶子结点的个数；用c语言实现

下面是统计二叉树中叶子结点个数的实现代码：

#include <stdio.h>
#include <stdlib.h>

typedef struct node {
    int data;
    struct node *left;
    struct node *right;
} Node;

// 创建二叉树
Node* createTree() {
    Node *root = (Node *) malloc(sizeof(Node));
    root->data = 1;
    root->left = (Node *) malloc(sizeof(Node));
    root->left->data = 2;
    root->left->left = (Node *) malloc(sizeof(Node));
    root->left->left->data = 4;
    root->left->left->left = NULL;
    root->left->left->right = NULL;
    root->left->right = (Node *) malloc(sizeof(Node));
    root->left->right->data = 5;
    root->left->right->left = NULL;
    root->left->right->right = NULL;
    root->right = (Node *) malloc(sizeof(Node));
    root->right->data = 3;
    root->right->left = (Node *) malloc(sizeof(Node));
    root->right->left->data = 6;
    root->right->left->left = NULL;
    root->right->left->right = NULL;
    root->right->right = (Node *) malloc(sizeof(Node));
    root->right->right->data = 7;
    root->right->right->left = NULL;
    root->right->right->right = NULL;
    return root;
}

// 统计二叉树中叶子结点个数
int countLeaves(Node* root) {
    if (root == NULL)
        return 0;
    if (root->left == NULL && root->right == NULL)
        return 1;
    return countLeaves(root->left) + countLeaves(root->right);
}

int main() {
    Node *root = createTree();
    int count = countLeaves(root);
    printf("Leaves count: %d\n", count);
    return 0;
}

输出结果为：

Leaves count: 4